Hey Respected Doctor I Had Sex With My Gf And

Hey respected doctor
i had sex with my gf and she take an unwanted 72 after five days she had her periods but after the period over we again had sex and she again take unwanted 72 within 10 days of taking previous unwanted 72
now she had missed her periods from last 10 days we had a test and the result is negative
what is this happening and what are the problems please tell